chore+fix: repo hygiene, code-review fixes, audit cleanup

Three independent code reviews + a security audit produced ~200 findings. This commit lands the high-impact subset. Tests pass (53), typecheck clean, eslint clean (3 minor exhaustive-deps warnings left). REPO HYGIENE - Add .editorconfig, .prettierrc.json, .prettierignore. - Add ESLint flat config (.eslintrc.cjs) — correctness-focused, no style rules (Prettier owns formatting). - Add `format` / `format:check` / `lint` npm scripts. - Add CHANGELOG.md (Keep a Changelog format, back-filled to 0.1.x). - Reformat all source via Prettier so future diffs stay small. DATA SAFETY (src/main/store.ts) - Atomic write (tmp + rename) with retry on transient EBUSY/EPERM — was non-atomic writeFileSync, vulnerable to truncation on power loss. - On corrupt JSON, rename to `app-state.json.corrupt-<ts>` instead of silently overwriting the user's exercises/history with defaults. - Validate parsed shape before merging — reject arrays/scalars where objects expected; per-field array checks. - Strip `id` from incoming patches in updateExercise/updateChallenge — a runtime caller (IPC) could otherwise smuggle id changes through. - clearHistory now refuses an unbounded wipe (no beforeTs => no-op); callers must pass an explicit boundary. - unref() the debounce timer so it doesn't keep the event loop alive. SECURITY (src/main/*) - gsi-server: hard 256 KB body cap (was unbounded — local OOM vector), reject any Origin/Sec-Fetch-Site header (blocks browser CSRF from visited pages), require application/json Content-Type, generic 400 on parse error (no error string echo to client), closeAllConnections + async close on stop. - dota2: validate auth.token from payload with timingSafeEqual against the per-install token — was unauthenticated, any local process could forge match-end events. Narrow object shape before spread-merge to avoid throws on hostile payloads like {player:"x"}. Reset latest / prevState after match_end so the next match starts clean. - ipc: gate `dev:simulateMatchEnd` registration behind `!app.isPackaged` so it does not exist in shipped builds. - preload: gate the matching `simulateMatchEnd` export behind `import.meta.env.MODE !== 'production'` so the bundler dead-code- eliminates it from the production preload bundle. - windows: shell.openExternal allowlist (http/https/mailto only) — was forwarding any URL, including file:/javascript:/custom URI handlers (some Windows handlers have been RCE vectors). will-navigate blocks navigation to anywhere except file:// or the dev URL. CORRECTNESS (src/main/* + src/shared/*) - shared/types.ts isQuietAt: fix wrap-around + day-of-week filter. With from=22:00 to=07:00 days=[Mon..Fri], the window started THE PREVIOUS DAY when we're in the AM half — old code checked today's day-of-week and got the wrong answer Sat 02:00 and Mon 01:00. Now the filter is evaluated against the window's START day. Also reject malformed HH:MM strings instead of producing NaN. - scheduler: call broadcastState() after firing exercises so the renderer's Dashboard/Exercises pages don't show stale nextFireAt until the next state-changing IPC. Guard powerMonitor listeners against double-registration on dev hot-reload. - dota2: fix `launchOptionStatus = steamRunning ? 'queued' : 'queued'` tautology — both branches now correctly read 'queued'. - steam-launch-options: replace `require('node:fs')` inside atomicWrite with the top-level import; retry on transient EBUSY/EPERM. CORRECTNESS (src/renderer/*) - lib/history.ts: replace `today.getTime() - i * MS_DAY` arithmetic with `setDate(date - i)` calendar arithmetic in dailyRepsRange and currentStreak — DST transitions shift epoch math by ±1h and cause dayKey() to emit duplicate or missing days at the boundary. - lib/icon.tsx: restrict name lookup to ICON_CHOICES set — an arbitrary string from a corrupted state file could otherwise resolve to unrelated Lucide exports and crash the renderer. - lib/format.ts: guard formatCountdown against NaN/Infinity. - i18n/index.ts: replace regex-based interpolation with split/join so variable values containing regex metacharacters interpolate literally; warn in dev on missing keys; clamp pluralRu(-N) via abs. - ReminderApp: keyboard shortcuts moved INTO ExerciseReminder so Enter respects the stepper's `adjusted` flag (was always passing planned reps). Stepper capped at 5× planned. Don't hijack Space when a button is focused. `key={exercise.id+nextFireAt}` forces a fresh component for back-to-back reminders so stepper state resets. Match summary view gets Esc-to-close. Functional setMode in onMarkDone avoids races against stale `mode.done`. - UpdaterCard: guard against NaN/Infinity in download-progress events (electron-updater fires early events with undefined fields). - Games: gate DevPanel behind `import.meta.env.DEV` in addition to the main-side IPC gate, and narrow the `simulateMatchEnd` access. - Add aria-labels for the +/- stepper buttons (i18n keys added). TESTS - +2 quiet-hours tests covering wrap-around + day-filter combo and malformed HH:MM fallback. Total 53 passing. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-18 23:04:49 +07:00
parent d6f94ee1c9
commit f3367e09de
44 changed files with 3694 additions and 285 deletions
--- a/.editorconfig
+++ b/.editorconfig
@@ -0,0 +1,18 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.{md,markdown}]
+trim_trailing_whitespace = false
+
+[*.{ps1,psm1,psd1}]
+end_of_line = crlf
+
+[Makefile]
+indent_style = tab
--- a/.eslintrc.cjs
+++ b/.eslintrc.cjs
@@ -0,0 +1,63 @@
+/**
+ * ESLint focuses on correctness, NOT style — Prettier owns formatting.
+ * Stylistic rules that fight Prettier are off.
+ */
+module.exports = {
+  root: true,
+  env: { browser: true, node: true, es2022: true },
+  parser: '@typescript-eslint/parser',
+  parserOptions: {
+    ecmaVersion: 2022,
+    sourceType: 'module',
+    ecmaFeatures: { jsx: true }
+  },
+  plugins: ['@typescript-eslint', 'react', 'react-hooks'],
+  settings: { react: { version: 'detect' } },
+  extends: [
+    'eslint:recommended',
+    'plugin:@typescript-eslint/recommended',
+    'plugin:react/recommended',
+    'plugin:react-hooks/recommended'
+  ],
+  rules: {
+    // React 17+ JSX transform — no need to import React in scope.
+    'react/react-in-jsx-scope': 'off',
+    'react/prop-types': 'off', // we use TS
+
+    // Hooks correctness — high signal.
+    'react-hooks/rules-of-hooks': 'error',
+    'react-hooks/exhaustive-deps': 'warn',
+
+    // TS — pragmatic, not strict.
+    '@typescript-eslint/no-explicit-any': 'warn',
+    '@typescript-eslint/no-unused-vars': [
+      'warn',
+      { argsIgnorePattern: '^_', varsIgnorePattern: '^_' }
+    ],
+    '@typescript-eslint/no-non-null-assertion': 'off',
+
+    // Vanilla — common bugs.
+    'no-console': ['warn', { allow: ['warn', 'error', 'info'] }],
+    'no-debugger': 'error',
+    'prefer-const': 'warn',
+    eqeqeq: ['error', 'always', { null: 'ignore' }]
+  },
+  ignorePatterns: [
+    'node_modules',
+    'out',
+    'release',
+    'dist',
+    '*.tsbuildinfo',
+    'src/preload/index.d.ts'
+  ],
+  overrides: [
+    {
+      files: ['**/*.test.ts', '**/*.test.tsx'],
+      env: { node: true }
+    },
+    {
+      files: ['*.config.js', '*.config.ts', 'electron.vite.config.ts'],
+      rules: { '@typescript-eslint/no-var-requires': 'off' }
+    }
+  ]
+}
--- a/.prettierignore
+++ b/.prettierignore
@@ -0,0 +1,8 @@
+node_modules
+out
+release
+dist
+package-lock.json
+*.tsbuildinfo
+resources/**/*.ico
+resources/**/*.png
--- a/.prettierrc.json
+++ b/.prettierrc.json
@@ -0,0 +1,18 @@
+{
+  "semi": false,
+  "singleQuote": true,
+  "trailingComma": "none",
+  "printWidth": 80,
+  "tabWidth": 2,
+  "arrowParens": "always",
+  "bracketSpacing": true,
+  "endOfLine": "lf",
+  "overrides": [
+    {
+      "files": ["*.md", "*.markdown"],
+      "options": {
+        "proseWrap": "preserve"
+      }
+    }
+  ]
+}
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -0,0 +1,96 @@
+# Changelog
+
+Все заметные изменения проекта документируются здесь.
+Формат основан на [Keep a Changelog](https://keepachangelog.com/ru/1.1.0/),
+проект следует [Semantic Versioning](https://semver.org/lang/ru/).
+
+## [Unreleased]
+
+### Added
+
+- Prettier + ESLint конфиги, скрипты `npm run format` / `npm run lint`.
+- `.editorconfig` для единообразного оформления между редакторами.
+
+## [0.5.1] — 2026-05-18
+
+### Fixed
+
+- **Auto-update архитектурно переписан.** Раньше `publish.url` включал
+  `${version}` и запекался в каждый билд — установленные копии видели
+  только свой собственный релиз. Введён фиксированный
+  `…/releases/download/update-channel`, который никогда не меняется.
+- Hourly auto-проверка работает в silent-режиме: транзитные сетевые
+  ошибки (504, TLS drops) больше не показывают красный баннер
+  «Ошибка проверки». Только ручной клик «Проверить» поднимает ошибку.
+- Boot-check ретраит 3 раза с backoff 30s/2m/5m.
+- В `Up to date` показывается «проверено N мин назад».
+- `release.ps1` теперь публикует в три-четыре места одной командой:
+  vX.Y.Z, update-channel, и переданные `-BridgeTags` для миграции
+  пользователей со старых версий.
+- `upload-release-assets.ps1` ретраит curl до 4 раз с backoff на 504 /
+  TLS-сбрасывание; до ретрая проверяет, не залился ли файл на самом
+  деле (Gitea часто принимает body, но таймаутит ответ).
+- Скрипты — ASCII-only (PS5.1 без BOM падает на em-dash).
+
+### Removed
+
+- `.gitea/workflows/*.yml` — Gitea Actions без настроенных runners
+  оставляли queued runs в репозитории. Релизим через `release.ps1`.
+
+## [0.5.0] — 2026-05-18
+
+### Added
+
+- **История + стрики.** Каждое выполненное упражнение пишется в
+  `app-state.json` (cap 10k записей, trim oldest 10% на overflow).
+  Heatmap-календарь 12 недель на Dashboard, ежедневный счётчик
+  «сделано сегодня», серия дней подряд (с grace-периодом за вчера).
+- **Тихие часы.** Окно времени, в которое напоминания подавляются.
+  Поддержка wrap-around (22:00 → 08:00) и фильтра по дням недели.
+- **Частичное выполнение.** Степпер `−/+` в окне напоминания: можно
+  отметить «сделал 5 из 10», в историю запишется честное число.
+- README.md на русском — описание, фичи, установка, dev-команды,
+  архитектура, стек.
+
+### Changed
+
+- `markDone(id, actualReps?)` принимает фактическое число повторений.
+
+### Tests
+
+- `+18` тестов (5 для тихих часов, 13 для истории/стриков). Всего 51.
+
+## [0.4.0] — 2026-05-17
+
+### Added
+
+- **Английская локализация.** Самописная i18n: плоский словарь
+  ~200 ключей × 2 языка + хук `useT()` + плюрализация (CLDR rules
+  для RU: one/few/many).
+- Селектор языка в Settings, переключение мгновенное.
+
+## [0.3.x] — 2026-05-17
+
+Серия мелких релизов с дизайн-итерациями (Apple iOS / macOS aesthetic):
+шрифты Plus Jakarta Sans + Bricolage Grotesque, светлая/тёмная/системная
+тема, vibrancy sidebar, iOS-grouped lists, spring-анимации.
+
+## [0.2.0] — 2026-05-16
+
+### Added
+
+- Dota 2 Game State Integration: локальный HTTP-сервер парсит callbacks
+  от Steam, после Победа/Поражение показывает «причитающиеся»
+  повторения (например `10 смертей × 3 = 30 приседаний`).
+
+## [0.1.x] — 2026-05-15 .. 2026-05-16
+
+Первые публичные сборки: ядро напоминаний (упражнения, интервалы,
+иконки), системный трей, автозапуск с Windows, native-уведомления,
+NSIS-инсталлятор, auto-update через electron-updater.
+
+[Unreleased]: https://xn--90adajar8af4h.xn--p1ai/git/AnRil/laude/compare/v0.5.1...HEAD
+[0.5.1]: https://xn--90adajar8af4h.xn--p1ai/git/AnRil/laude/releases/tag/v0.5.1
+[0.5.0]: https://xn--90adajar8af4h.xn--p1ai/git/AnRil/laude/releases/tag/v0.5.0
+[0.4.0]: https://xn--90adajar8af4h.xn--p1ai/git/AnRil/laude/releases/tag/v0.4.0
+[0.2.0]: https://xn--90adajar8af4h.xn--p1ai/git/AnRil/laude/releases/tag/v0.2.0
--- a/RELEASING.md
+++ b/RELEASING.md
@@ -30,10 +30,10 @@ latest.yml                                  # манифест: версия +
 И они одновременно публикуются в **три-четыре места** на Gitea:

 | Release tag       | Назначение                                                   |
-|------------------|-------------------------------------------------------------|
+| ----------------- | ------------------------------------------------------------ |
 | `vX.Y.Z`          | Архив + changelog для людей                                  |
 | `update-channel`  | **Фиксированный URL для auto-updater** (никогда не меняется) |
-| `vN.M.K` (bridge)| Мост: чтобы клиенты на старых версиях нашли обновление       |
+| `vN.M.K` (bridge) | Мост: чтобы клиенты на старых версиях нашли обновление       |

 ### Что приложение запекает в бинарник

--- a/package-lock.json
+++ b/package-lock.json
--- a/package.json
+++ b/package.json
@@ -14,6 +14,9 @@
    "typecheck": "npm run typecheck:node && npm run typecheck:web",
    "test": "vitest",
    "test:run": "vitest run",
+    "format": "prettier --write \"src/**/*.{ts,tsx,css}\" \"*.{json,md}\" \".github/**/*.yml\"",
+    "format:check": "prettier --check \"src/**/*.{ts,tsx,css}\" \"*.{json,md}\"",
+    "lint": "eslint src --ext .ts,.tsx --max-warnings 0",
    "dist": "electron-vite build && electron-builder --win --x64",
    "dist:dir": "electron-vite build && electron-builder --win --x64 --dir",
    "publish": "electron-vite build && electron-builder --win --x64 --publish always",
@@ -33,12 +36,18 @@
    "@types/node": "^22.19.19",
    "@types/react": "^18.3.12",
    "@types/react-dom": "^18.3.1",
+    "@typescript-eslint/eslint-plugin": "^8.15.0",
+    "@typescript-eslint/parser": "^8.15.0",
    "@vitejs/plugin-react": "^4.3.3",
    "autoprefixer": "^10.4.20",
    "electron": "^33.2.0",
    "electron-builder": "^25.1.8",
    "electron-vite": "^2.3.0",
+    "eslint": "^8.57.1",
+    "eslint-plugin-react": "^7.37.2",
+    "eslint-plugin-react-hooks": "^5.0.0",
    "postcss": "^8.4.49",
+    "prettier": "^3.4.1",
    "tailwindcss": "^3.4.15",
    "typescript": "^5.6.3",
    "vite": "^5.4.11",
--- a/src/main/autostart.ts
+++ b/src/main/autostart.ts
@@ -17,5 +17,8 @@ export function isAutostartEnabled(): boolean {
 }

 export function wasStartedHidden(): boolean {
-  return process.argv.includes(HIDDEN_FLAG) || app.getLoginItemSettings().wasOpenedAsHidden
+  return (
+    process.argv.includes(HIDDEN_FLAG) ||
+    app.getLoginItemSettings().wasOpenedAsHidden
+  )
 }
--- a/src/main/games/dota2.ts
+++ b/src/main/games/dota2.ts
@@ -1,6 +1,12 @@
-import { existsSync, mkdirSync, readFileSync, unlinkSync, writeFileSync } from 'node:fs'
+import {
+  existsSync,
+  mkdirSync,
+  readFileSync,
+  unlinkSync,
+  writeFileSync
+} from 'node:fs'
 import { join } from 'node:path'
-import { randomBytes } from 'node:crypto'
+import { randomBytes, timingSafeEqual } from 'node:crypto'
 import { app } from 'electron'
 import type { GameProvider, ProviderEventHandler } from './provider'
 import { findGameInstall } from './steam'
@@ -21,6 +27,7 @@ const LAUNCH_OPTION = '-gamestateintegration'

 type DotaGsi = {
  provider?: { name?: string }
+  auth?: { token?: string }
  map?: {
    game_state?: string
    win_team?: 'radiant' | 'dire' | 'none'
@@ -38,6 +45,19 @@ type DotaGsi = {
  }
 }

+/**
+ * Constant-time string equality. Avoids early-exit timing oracles that could
+ * leak the token byte-by-byte to a local attacker who can measure response
+ * latency on the loopback HTTP server. (Practical risk is tiny; correctness
+ * matters anyway.)
+ */
+function safeEqualStrings(a: string, b: string): boolean {
+  const A = Buffer.from(a, 'utf-8')
+  const B = Buffer.from(b, 'utf-8')
+  if (A.length !== B.length) return false
+  return timingSafeEqual(A, B)
+}
+
 function tokenStorePath(): string {
  return join(app.getPath('userData'), 'dota2-gsi-token.txt')
 }
@@ -115,7 +135,10 @@ export class Dota2Provider implements GameProvider {
      if (present) launchOptionStatus = 'applied'
      else {
        steamRunning = await isSteamRunning()
-        launchOptionStatus = steamRunning ? 'queued' : 'queued'
+        // Either Steam is open (we can't write while it runs -> 'queued') or
+        // closed (apply on next ensureLaunchOption call -> still queued until
+        // the watcher tick actually writes). 'queued' is correct for both.
+        launchOptionStatus = 'queued'
      }
    }
    return {
@@ -134,7 +157,8 @@ export class Dota2Provider implements GameProvider {
  async install(): Promise<void> {
    if (!this.installPath) {
      const status = await this.detect()
-      if (!status.installPath) throw new Error('Dota 2 не найдена в Steam-библиотеках')
+      if (!status.installPath)
+        throw new Error('Dota 2 не найдена в Steam-библиотеках')
    }
    const dir = cfgDir(this.installPath!)
    if (!existsSync(dir)) mkdirSync(dir, { recursive: true })
@@ -157,7 +181,13 @@ export class Dota2Provider implements GameProvider {

  async start(emit: ProviderEventHandler): Promise<void> {
    this.emit = emit
-    this.unregister = registerGsiRoute(ROUTE, (payload) => this.handle(payload as DotaGsi))
+    // Defensive double-register guard: free any previous registration first.
+    this.unregister?.()
+    this.unregister = registerGsiRoute(ROUTE, (payload) => {
+      // Runtime shape check — payload comes from a network socket.
+      if (typeof payload !== 'object' || payload === null) return
+      this.handle(payload as DotaGsi)
+    })
  }

  async stop(): Promise<void> {
@@ -169,10 +199,34 @@ export class Dota2Provider implements GameProvider {
  }

  private handle(g: DotaGsi): void {
-    // Track latest snapshot so we have stats when the transition fires.
-    if (g.player || g.map) this.latest = { ...this.latest, ...g, player: { ...this.latest?.player, ...g.player }, map: { ...this.latest?.map, ...g.map } }
+    // Verify the per-install token. Dota always sends auth.token; anything
+    // without it (or with the wrong one) is some other process on localhost
+    // trying to fake a match-end event.
+    const incoming = g.auth?.token
+    if (
+      typeof incoming !== 'string' ||
+      !safeEqualStrings(incoming, this.token)
+    ) {
+      return
+    }

-    const state = g.map?.game_state ?? this.latest?.map?.game_state
+    // Narrow the shape before spread-merging. A payload like `{player:"x"}`
+    // would otherwise let `{...this.latest?.player, ...g.player}` throw.
+    const playerObj =
+      typeof g.player === 'object' && g.player !== null ? g.player : undefined
+    const mapObj =
+      typeof g.map === 'object' && g.map !== null ? g.map : undefined
+
+    if (playerObj || mapObj) {
+      this.latest = {
+        ...this.latest,
+        ...g,
+        player: { ...this.latest?.player, ...playerObj },
+        map: { ...this.latest?.map, ...mapObj }
+      }
+    }
+
+    const state = mapObj?.game_state ?? this.latest?.map?.game_state
    if (!state) return

    const prev = this.prevState
@@ -209,6 +263,11 @@ export class Dota2Provider implements GameProvider {
          }
        }
      })
+
+      // Reset stale state so the NEXT match starts from a clean slate even if
+      // the user re-enters the same lobby or Dota's GSI restarts mid-session.
+      this.latest = undefined
+      this.prevState = undefined
    }
  }
 }
--- a/src/main/games/gsi-server.ts
+++ b/src/main/games/gsi-server.ts
@@ -1,22 +1,63 @@
-import { createServer, type IncomingMessage, type Server, type ServerResponse } from 'node:http'
+import {
+  createServer,
+  type IncomingMessage,
+  type Server,
+  type ServerResponse
+} from 'node:http'

-export type GsiHandler = (payload: unknown, headers: Record<string, string | string[] | undefined>) => void
+export type GsiHandler = (
+  payload: unknown,
+  headers: Record<string, string | string[] | undefined>
+) => void

 const PORT = 4701
+/**
+ * Hard cap on incoming POST body. Real Dota GSI payloads are ~8 KB; anything
+ * larger is either a bug or a malicious local client trying to OOM us.
+ */
+const MAX_BODY_BYTES = 256 * 1024

 let server: Server | null = null
 const handlers: Map<string, GsiHandler> = new Map()

-function getBody(req: IncomingMessage): Promise<Buffer> {
+function readBody(req: IncomingMessage): Promise<Buffer> {
  return new Promise((resolve, reject) => {
+    let received = 0
    const chunks: Buffer[] = []
-    req.on('data', (c) => chunks.push(c as Buffer))
+    req.on('data', (c: Buffer) => {
+      received += c.length
+      if (received > MAX_BODY_BYTES) {
+        // Drop the connection so we don't keep buffering.
+        req.destroy(new Error('body too large'))
+        reject(new Error('body too large'))
+        return
+      }
+      chunks.push(c)
+    })
    req.on('end', () => resolve(Buffer.concat(chunks)))
    req.on('error', reject)
  })
 }

-async function onRequest(req: IncomingMessage, res: ServerResponse): Promise<void> {
+async function onRequest(
+  req: IncomingMessage,
+  res: ServerResponse
+): Promise<void> {
+  // Reject browser-originated requests outright. Legitimate Dota GSI POSTs
+  // never include an Origin header; any value here means a webpage is poking
+  // our localhost endpoint via cross-origin fetch, which we never want.
+  if (req.headers.origin) {
+    res.statusCode = 403
+    res.end()
+    return
+  }
+  // Same intent for Sec-Fetch-Site: browsers always set it, Dota never does.
+  if (req.headers['sec-fetch-site']) {
+    res.statusCode = 403
+    res.end()
+    return
+  }
+
  const route = (req.url ?? '/').split('?')[0]
  const handler = handlers.get(route)
  if (!handler) {
@@ -29,17 +70,38 @@ async function onRequest(req: IncomingMessage, res: ServerResponse): Promise<voi
    res.end()
    return
  }
+  // Require JSON content-type. Browsers' "simple" requests in no-cors mode
+  // can only send text/plain or form-encoded — locking to application/json
+  // shrinks the cross-origin attack surface further.
+  const ct = String(req.headers['content-type'] ?? '').toLowerCase()
+  if (!ct.includes('application/json')) {
+    res.statusCode = 415
+    res.end()
+    return
+  }
+
+  let payload: unknown
  try {
-    const body = await getBody(req)
+    const body = await readBody(req)
    const text = body.toString('utf-8')
-    const payload = text.length > 0 ? JSON.parse(text) : {}
+    payload = text.length > 0 ? JSON.parse(text) : {}
+  } catch (err) {
+    // Log the real reason locally; do not echo it to the client.
+    console.warn('[gsi] bad request:', err instanceof Error ? err.message : err)
+    res.statusCode = 400
+    res.end()
+    return
+  }
+
+  try {
    handler(payload, req.headers)
    res.statusCode = 200
    res.setHeader('Content-Type', 'text/plain')
    res.end('ok')
  } catch (err) {
+    console.error('[gsi] handler threw:', err)
    res.statusCode = 500
-    res.end(String(err))
+    res.end()
  }
 }

@@ -52,16 +114,26 @@ export async function startGsiServer(): Promise<void> {
  })
 }

-export function stopGsiServer(): void {
-  if (server) {
-    server.close()
+export async function stopGsiServer(): Promise<void> {
+  if (!server) return
+  const s = server
  server = null
-  }
+  // Free pending sockets so close() can resolve quickly even while Dota holds
+  // a long-poll connection open.
+  s.closeAllConnections?.()
+  await new Promise<void>((resolve) => s.close(() => resolve()))
 }

-export function registerGsiRoute(route: string, handler: GsiHandler): () => void {
+export function registerGsiRoute(
+  route: string,
+  handler: GsiHandler
+): () => void {
  handlers.set(route, handler)
-  return () => handlers.delete(route)
+  return () => {
+    // Only delete if we're still the registered handler — protects against
+    // double-register + unregister races where a newer handler took our slot.
+    if (handlers.get(route) === handler) handlers.delete(route)
+  }
 }

 export function getGsiBaseUrl(): string {
--- a/src/main/games/provider.ts
+++ b/src/main/games/provider.ts
@@ -6,7 +6,10 @@ export type MatchEndPayload = {
  stats: Partial<Record<GameStat, number>>
 }

-export type ProviderEventHandler = (event: { type: 'match_end'; payload: MatchEndPayload }) => void
+export type ProviderEventHandler = (event: {
+  type: 'match_end'
+  payload: MatchEndPayload
+}) => void

 export interface GameProvider {
  readonly id: GameId
--- a/src/main/games/registry.ts
+++ b/src/main/games/registry.ts
@@ -5,7 +5,6 @@ import { startGsiServer, stopGsiServer } from './gsi-server'
 import { onLaunchOptionsApplied } from './steam-launch-options'
 import { IPC } from '@shared/ipc'
 import type {
-  Challenge,
  ChallengeResult,
  GameId,
  GameStatus,
@@ -21,7 +20,10 @@ const providers: Record<GameId, GameProvider> = {

 let running = false

-async function onMatchEnd(gameId: GameId, payload: MatchEndPayload): Promise<void> {
+async function onMatchEnd(
+  gameId: GameId,
+  payload: MatchEndPayload
+): Promise<void> {
  const provider = providers[gameId]
  const challenges = getChallenges().filter(
    (c) => c.gameId === gameId && c.enabled
@@ -136,7 +138,10 @@ export function broadcastGames(games: GameStatus[]): void {
 }

 // Simulate a match-end for debugging (called from IPC in dev).
-export function simulateMatchEnd(id: GameId, stats: Partial<Record<string, number>>): void {
+export function simulateMatchEnd(
+  id: GameId,
+  stats: Partial<Record<string, number>>
+): void {
  void onMatchEnd(id, {
    durationMs: (stats.duration_min ?? 35) * 60_000,
    won: stats.won === 1,
--- a/src/main/games/steam-launch-options.ts
+++ b/src/main/games/steam-launch-options.ts
@@ -4,6 +4,7 @@ import {
  existsSync,
  readFileSync,
  readdirSync,
+  renameSync,
  writeFileSync
 } from 'node:fs'
 import { join } from 'node:path'
@@ -53,7 +54,10 @@ function findKey(node: VdfNode, target: string): string | undefined {
  return undefined
 }

-function findCaseInsensitive(node: VdfNode, ...keys: string[]): VdfNode | undefined {
+function findCaseInsensitive(
+  node: VdfNode,
+  ...keys: string[]
+): VdfNode | undefined {
  let cur: VdfNode = node
  for (const key of keys) {
    const found: string | undefined = findKey(cur, key)
@@ -80,7 +84,11 @@ function findOrCreatePath(node: VdfNode, ...keys: string[]): VdfNode {
  return cur
 }

-function getAppNode(parsed: VdfNode, appId: string, create: boolean): VdfNode | undefined {
+function getAppNode(
+  parsed: VdfNode,
+  appId: string,
+  create: boolean
+): VdfNode | undefined {
  if (create) {
    const apps = findOrCreatePath(
      parsed,
@@ -116,13 +124,28 @@ function writeBackup(path: string): void {
 }

 function atomicWrite(path: string, contents: string): void {
-  // Write to temp then rename (atomic on Windows for same directory).
+  // Write to temp then rename (atomic on Windows for same directory). Retry a
+  // few times on transient EBUSY/EPERM (AV scanners and OneDrive sometimes
+  // hold a handle briefly during a Steam config rewrite).
  const tmp = path + '.exr.tmp'
+  const delays = [0, 50, 200]
+  let lastErr: unknown
+  for (const delay of delays) {
+    if (delay > 0) {
+      const until = Date.now() + delay
+      while (Date.now() < until) {
+        /* spin */
+      }
+    }
+    try {
      writeFileSync(tmp, contents, 'utf-8')
-  // fs.renameSync replaces destination atomically on Windows
-  // eslint-disable-next-line @typescript-eslint/no-var-requires
-  const fs = require('node:fs') as typeof import('node:fs')
-  fs.renameSync(tmp, path)
+      renameSync(tmp, path)
+      return
+    } catch (e) {
+      lastErr = e
+    }
+  }
+  throw lastErr
 }

 function modifyLaunchOptions(
@@ -183,7 +206,9 @@ export async function isLaunchOptionPresent(
      const parsed = parseVdf(raw)
      const app = getAppNode(parsed, appId, false)
      if (!app) continue
-      const loKey = Object.keys(app).find((k) => k.toLowerCase() === 'launchoptions')
+      const loKey = Object.keys(app).find(
+        (k) => k.toLowerCase() === 'launchoptions'
+      )
      if (!loKey) continue
      const value = String(app[loKey] ?? '')
      if (value.includes(option)) return true
@@ -194,7 +219,10 @@ export async function isLaunchOptionPresent(
  return false
 }

-async function applyOptionToAllConfigs(appId: string, option: string): Promise<void> {
+async function applyOptionToAllConfigs(
+  appId: string,
+  option: string
+): Promise<void> {
  const paths = await getLocalConfigPaths()
  for (const p of paths) {
    modifyLaunchOptions(p, appId, (current) => {
@@ -204,7 +232,10 @@ async function applyOptionToAllConfigs(appId: string, option: string): Promise<v
  }
 }

-async function removeOptionFromAllConfigs(appId: string, option: string): Promise<void> {
+async function removeOptionFromAllConfigs(
+  appId: string,
+  option: string
+): Promise<void> {
  const paths = await getLocalConfigPaths()
  for (const p of paths) {
    modifyLaunchOptions(p, appId, (current) => {
--- a/src/main/games/steam.ts
+++ b/src/main/games/steam.ts
@@ -6,12 +6,14 @@ import { parseVdf, type VdfNode } from './vdf'

 const execAsync = promisify(exec)

-async function regQuery(key: string, valueName: string): Promise<string | undefined> {
+async function regQuery(
+  key: string,
+  valueName: string
+): Promise<string | undefined> {
  try {
-    const { stdout } = await execAsync(
-      `reg query "${key}" /v ${valueName}`,
-      { windowsHide: true }
-    )
+    const { stdout } = await execAsync(`reg query "${key}" /v ${valueName}`, {
+      windowsHide: true
+    })
    const m = stdout.match(/REG_SZ\s+(.+)/)
    return m?.[1]?.trim()
  } catch {
--- a/src/main/games/vdf.ts
+++ b/src/main/games/vdf.ts
@@ -4,7 +4,10 @@
 export type VdfNode = { [key: string]: string | VdfNode }

 class Cursor {
-  constructor(public src: string, public pos: number = 0) {}
+  constructor(
+    public src: string,
+    public pos: number = 0
+  ) {}
  peek(): string {
    return this.src[this.pos] ?? ''
  }
@@ -51,7 +54,12 @@ function readToken(c: Cursor): string {
  }
  if (c.peek() === '{' || c.peek() === '}') return c.next()
  let out = ''
-  while (!c.eof() && !/\s/.test(c.peek()) && c.peek() !== '{' && c.peek() !== '}') {
+  while (
+    !c.eof() &&
+    !/\s/.test(c.peek()) &&
+    c.peek() !== '{' &&
+    c.peek() !== '}'
+  ) {
    out += c.next()
  }
  return out
--- a/src/main/index.ts
+++ b/src/main/index.ts
@@ -1,5 +1,9 @@
 import { app, BrowserWindow, nativeTheme, systemPreferences } from 'electron'
-import { createMainWindow, createReminderWindow, showMainWindow } from './windows'
+import {
+  createMainWindow,
+  createReminderWindow,
+  showMainWindow
+} from './windows'
 import { registerIpc } from './ipc'
 import { startScheduler, stopScheduler } from './scheduler'
 import { createTray } from './tray'
@@ -27,8 +31,7 @@ if (!gotLock) {
    registerIpc()
    createTray()

-    const hidden =
-      wasStartedHidden() || getState().settings.startMinimized
+    const hidden = wasStartedHidden() || getState().settings.startMinimized
    createMainWindow(!hidden)
    // Pre-create the reminder window so first-trigger is instant (no load lag).
    createReminderWindow()
@@ -51,7 +54,8 @@ if (!gotLock) {
        try {
          const color = '#' + systemPreferences.getAccentColor()
          for (const win of BrowserWindow.getAllWindows()) {
-            if (!win.isDestroyed()) win.webContents.send(IPC.evtAccentChanged, color)
+            if (!win.isDestroyed())
+              win.webContents.send(IPC.evtAccentChanged, color)
          }
        } catch {
          // ignore
--- a/src/main/ipc.ts
+++ b/src/main/ipc.ts
@@ -1,4 +1,11 @@
-import { ipcMain, nativeTheme, systemPreferences, BrowserWindow, app, shell } from 'electron'
+import {
+  ipcMain,
+  nativeTheme,
+  systemPreferences,
+  BrowserWindow,
+  app,
+  shell
+} from 'electron'
 import { IPC } from '@shared/ipc'
 import type { Challenge, Exercise, GameId, Settings } from '@shared/types'
 import {
@@ -52,11 +59,14 @@ export function registerIpc(): void {
    }
  )

-  ipcMain.handle(IPC.updateExercise, (_e, id: string, patch: Partial<Exercise>) => {
+  ipcMain.handle(
+    IPC.updateExercise,
+    (_e, id: string, patch: Partial<Exercise>) => {
      const ex = updateExercise(id, patch)
      broadcastState()
      return ex
-  })
+    }
+  )

  ipcMain.handle(IPC.deleteExercise, (_e, id: string) => {
    const ok = deleteExercise(id)
@@ -75,14 +85,11 @@ export function registerIpc(): void {
    return ex
  })

-  ipcMain.handle(
-    IPC.markDone,
-    (_e, id: string, actualReps?: number) => {
+  ipcMain.handle(IPC.markDone, (_e, id: string, actualReps?: number) => {
    const ex = markDone(id, actualReps)
    broadcastState()
    return ex
-    }
-  )
+  })

  ipcMain.handle(IPC.snooze, (_e, id: string, minutes: number) => {
    const ex = snooze(id, minutes)
@@ -205,13 +212,17 @@ export function registerIpc(): void {

  ipcMain.handle(IPC.closeMatchSummary, () => hideReminderWindow())

-  // Dev helper: simulate a match end with given stats.
+  // Dev helper: simulate a match end with given stats. NEVER registered in
+  // packaged builds — a compromised renderer (XSS, malicious npm dep) could
+  // otherwise fabricate arbitrary match-end events at will.
+  if (!app.isPackaged) {
    ipcMain.handle(
      'dev:simulateMatchEnd',
      (_e, id: GameId, stats: Record<string, number>) => {
        simulateMatchEnd(id, stats)
      }
    )
+  }

  // Auto-updater
  ipcMain.handle(IPC.updaterStatus, () => getUpdaterStatus())
--- a/src/main/scheduler.ts
+++ b/src/main/scheduler.ts
@@ -4,10 +4,17 @@ import type { Tick } from '@shared/types'
 import { isQuietAt } from '@shared/types'
 import { getExercises, getSettings, updateExercise } from './store'
 import { fireReminder } from './notifications'
+import { broadcastState } from './state-actions'

+/**
+ * TICK_MS drives the per-second countdown UI; CHECK_MS gates the (cheaper)
+ * "is anything due to fire?" pass so we don't iterate exercises every second.
+ */
 const TICK_MS = 1000
 const CHECK_MS = 5000
+
 let tickHandle: NodeJS.Timeout | null = null
+let powerListenersArmed = false
 let lastCheckAt = 0
 let paused = false

@@ -16,21 +23,28 @@ function checkDueExercises(): void {
  const settings = getSettings()
  if (!settings.globalEnabled) return

-  // Inside the quiet window: defer all due fires to the next minute boundary.
-  // The next tick after the window closes will pick them up.
+  // Inside the quiet window: defer all due fires until it closes. The next
+  // CHECK_MS pass after the window ends will pick them up.
  if (isQuietAt(settings.quietHours, new Date())) return

  const now = Date.now()
  const exercises = getExercises()
+  let anyFired = false
  for (const ex of exercises) {
    if (!ex.enabled) continue
    if (ex.nextFireAt <= now) {
      const updated = updateExercise(ex.id, {
        nextFireAt: now + ex.intervalMinutes * 60_000
      })
-      if (updated) fireReminder(updated, settings.notificationMode)
+      if (updated) {
+        anyFired = true
+        fireReminder(updated, settings.notificationMode)
      }
    }
+  }
+  // Push fresh state so the renderer's Dashboard/Exercises pages don't show
+  // stale `nextFireAt` until the next state-changing IPC arrives.
+  if (anyFired) broadcastState()
 }

 function broadcastTicks(): void {
@@ -61,6 +75,11 @@ export function startScheduler(): void {
  // Run an immediate tick so renderer hydrates quickly.
  tick()

+  // Only attach powerMonitor listeners once per process — startScheduler may
+  // be invoked again after stopScheduler in dev hot-reload paths and we don't
+  // want the same handler firing N times after a resume.
+  if (!powerListenersArmed) {
+    powerListenersArmed = true
    powerMonitor.on('resume', () => {
      lastCheckAt = 0
      tick()
@@ -69,6 +88,7 @@ export function startScheduler(): void {
      lastCheckAt = 0
      tick()
    })
+  }
 }

 export function stopScheduler(): void {
--- a/src/main/store.ts
+++ b/src/main/store.ts
@@ -1,5 +1,12 @@
 import { app } from 'electron'
-import { existsSync, mkdirSync, readFileSync, writeFileSync } from 'node:fs'
+import {
+  existsSync,
+  mkdirSync,
+  readFileSync,
+  renameSync,
+  unlinkSync,
+  writeFileSync
+} from 'node:fs'
 import { join } from 'node:path'
 import { randomUUID } from 'node:crypto'
 import {
@@ -14,9 +21,15 @@ import {
  Settings
 } from '@shared/types'

-/** Keep at most this many entries (~3 years if ~10/day). Trim oldest. */
+/**
+ * Keep at most this many history entries (≈2.7 years at 10/day).
+ * When the cap is hit, drop oldest 10% so we don't trim on every write.
+ */
 const HISTORY_MAX = 10_000

+const WRITE_DEBOUNCE_MS = 1500
+const WRITE_RETRY_DELAYS = [50, 200, 800] // ms backoff on transient EBUSY/EPERM
+
 let cache: AppState | null = null
 let storePath = ''
 let pendingWrite: NodeJS.Timeout | null = null
@@ -66,26 +79,63 @@ function makeInitial(): AppState {
  }
 }

+/** Quarantine a corrupt state file so the user can recover it manually. */
+function quarantineCorrupt(p: string, reason: string): void {
+  try {
+    const stamp = new Date()
+      .toISOString()
+      .replace(/[:.]/g, '-')
+      .replace(/Z$/, '')
+    const dest = `${p}.corrupt-${stamp}`
+    renameSync(p, dest)
+    console.error(
+      `[store] app-state.json was unreadable (${reason}); ` +
+        `moved to ${dest} and starting fresh.`
+    )
+  } catch (e) {
+    console.error('[store] failed to quarantine corrupt state file:', e)
+  }
+}
+
+function isValidParsed(v: unknown): v is Partial<AppState> {
+  return typeof v === 'object' && v !== null && !Array.isArray(v)
+}
+
 function load(): AppState {
  const p = getStorePath()
  if (!existsSync(p)) {
    const initial = makeInitial()
-    writeFileSync(p, JSON.stringify(initial, null, 2), 'utf-8')
+    atomicWrite(p, JSON.stringify(initial, null, 2))
    return initial
  }
+  let raw: string
  try {
-    const raw = readFileSync(p, 'utf-8')
-    const parsed = JSON.parse(raw) as Partial<AppState>
-    return {
-      exercises: parsed.exercises ?? [],
-      settings: { ...DEFAULT_SETTINGS, ...(parsed.settings ?? {}) },
-      challenges: parsed.challenges ?? [],
-      gamesEnabled: parsed.gamesEnabled ?? {},
-      history: parsed.history ?? []
+    raw = readFileSync(p, 'utf-8')
+  } catch (e) {
+    console.error('[store] cannot read state file:', e)
+    return makeInitial() // do not quarantine — we can't read it anyway
  }
-  } catch {
+  let parsed: unknown
+  try {
+    parsed = JSON.parse(raw)
+  } catch (e) {
+    quarantineCorrupt(p, `JSON parse error: ${String(e)}`)
    return makeInitial()
  }
+  if (!isValidParsed(parsed)) {
+    quarantineCorrupt(p, `expected object, got ${typeof parsed}`)
+    return makeInitial()
+  }
+  return {
+    exercises: Array.isArray(parsed.exercises) ? parsed.exercises : [],
+    settings: { ...DEFAULT_SETTINGS, ...(parsed.settings ?? {}) },
+    challenges: Array.isArray(parsed.challenges) ? parsed.challenges : [],
+    gamesEnabled:
+      typeof parsed.gamesEnabled === 'object' && parsed.gamesEnabled !== null
+        ? parsed.gamesEnabled
+        : {},
+    history: Array.isArray(parsed.history) ? parsed.history : []
+  }
 }

 function appendHistory(
@@ -98,11 +148,10 @@ function appendHistory(
  const entry: HistoryEntry = { ts: Date.now(), exerciseId, action }
  if (actualReps !== undefined) entry.actualReps = actualReps
  state.history.push(entry)
-  // Cap size — trim oldest 10% when over limit, so we don't trim every write.
  if (state.history.length > HISTORY_MAX) {
    state.history = state.history.slice(-Math.floor(HISTORY_MAX * 0.9))
  }
-  scheduleWrite()
+  // Caller schedules the write; appendHistory itself is internal.
 }

 export function getHistory(sinceMs?: number): HistoryEntry[] {
@@ -115,17 +164,50 @@ export function clearHistory(beforeTs?: number): number {
  const state = getState()
  const before = state.history?.length ?? 0
  if (beforeTs == null) {
-    state.history = []
-  } else {
-    state.history = (state.history ?? []).filter((e) => e.ts >= beforeTs)
+    // Refuse a full wipe via IPC — callers must pass an explicit boundary.
+    // (Settings UI passes 0 to wipe everything; that's an opt-in.)
+    return 0
  }
+  state.history = (state.history ?? []).filter((e) => e.ts >= beforeTs)
  scheduleWrite()
  return before - (state.history?.length ?? 0)
 }

+/**
+ * Atomically write to `path` via a sibling .tmp file + rename. Retries a few
+ * times on transient EBUSY/EPERM (AV/OneDrive holding the file).
+ */
+function atomicWrite(path: string, contents: string): void {
+  const tmp = `${path}.tmp`
+  let lastErr: unknown
+  for (let i = 0; i <= WRITE_RETRY_DELAYS.length; i++) {
+    try {
+      writeFileSync(tmp, contents, 'utf-8')
+      renameSync(tmp, path)
+      return
+    } catch (e) {
+      lastErr = e
+      // best-effort cleanup of the stale .tmp
+      try {
+        if (existsSync(tmp)) unlinkSync(tmp)
+      } catch {
+        /* ignore */
+      }
+      const delay = WRITE_RETRY_DELAYS[i]
+      if (delay === undefined) break
+      // Synchronous sleep — write path is short and called outside the hot loop.
+      const until = Date.now() + delay
+      while (Date.now() < until) {
+        /* spin */
+      }
+    }
+  }
+  console.error('[store] atomic write failed after retries:', lastErr)
+}
+
 function flush(): void {
  if (!cache) return
-  writeFileSync(getStorePath(), JSON.stringify(cache, null, 2), 'utf-8')
+  atomicWrite(getStorePath(), JSON.stringify(cache, null, 2))
 }

 function scheduleWrite(): void {
@@ -133,7 +215,10 @@ function scheduleWrite(): void {
  pendingWrite = setTimeout(() => {
    pendingWrite = null
    flush()
-  }, 1500)
+  }, WRITE_DEBOUNCE_MS)
+  // Don't keep the event loop alive solely for a pending write — `before-quit`
+  // calls `flushNow()` and we explicitly want the process to exit on schedule.
+  pendingWrite.unref?.()
 }

 export function getState(): AppState {
@@ -178,9 +263,15 @@ export function updateExercise(
  const idx = state.exercises.findIndex((e) => e.id === id)
  if (idx === -1) return undefined
  const prev = state.exercises[idx]
-  const merged: Exercise = { ...prev, ...patch }
+  // Drop `id` from the patch even though the type forbids it — runtime callers
+  // (IPC) can still smuggle it through. We never let the id change.
+  const { id: _ignoredId, ...safePatch } = patch as Partial<Exercise>
+  const merged: Exercise = { ...prev, ...safePatch }
  // If interval changed, reschedule from now.
-  if (patch.intervalMinutes !== undefined && patch.intervalMinutes !== prev.intervalMinutes) {
+  if (
+    patch.intervalMinutes !== undefined &&
+    patch.intervalMinutes !== prev.intervalMinutes
+  ) {
    merged.nextFireAt = Date.now() + merged.intervalMinutes * 60_000
  }
  state.exercises[idx] = merged
@@ -258,7 +349,9 @@ export function updateChallenge(
  const state = getState()
  const idx = state.challenges.findIndex((c) => c.id === id)
  if (idx === -1) return undefined
-  state.challenges[idx] = { ...state.challenges[idx], ...patch }
+  // Same id-strip as updateExercise.
+  const { id: _ignoredId, ...safePatch } = patch as Partial<Challenge>
+  state.challenges[idx] = { ...state.challenges[idx], ...safePatch }
  scheduleWrite()
  return state.challenges[idx]
 }
--- a/src/main/windows.ts
+++ b/src/main/windows.ts
@@ -24,6 +24,48 @@ function windowIcon(): Electron.NativeImage | undefined {
  return undefined
 }

+/**
+ * Allowlist of schemes safe to hand to the OS via shell.openExternal.
+ * The renderer is hostile-by-default — XSS or a malicious dep could ask us
+ * to open `file:`, `javascript:`, `ms-msdt:`, `steam://install/...` etc.
+ * (Custom URI handlers have historically been RCE vectors.)
+ */
+const ALLOWED_EXTERNAL_SCHEMES = new Set(['http:', 'https:', 'mailto:'])
+
+function isSafeExternalUrl(url: string): boolean {
+  try {
+    return ALLOWED_EXTERNAL_SCHEMES.has(new URL(url).protocol)
+  } catch {
+    return false
+  }
+}
+
+function installSafeNavigation(win: BrowserWindow): void {
+  // Any popup attempt: open externally only if scheme is in our allowlist.
+  win.webContents.setWindowOpenHandler(({ url }) => {
+    if (isSafeExternalUrl(url)) {
+      void shell.openExternal(url)
+    } else {
+      console.warn(
+        '[windows] blocked openExternal for non-allowlisted URL:',
+        url
+      )
+    }
+    return { action: 'deny' }
+  })
+  // Renderer must never navigate the BrowserWindow to a third-party origin.
+  // We always load file:// or the dev URL; anything else is suspect.
+  win.webContents.on('will-navigate', (event, url) => {
+    const devUrl = process.env['ELECTRON_RENDERER_URL']
+    const allow =
+      url.startsWith('file://') || (devUrl && url.startsWith(devUrl))
+    if (!allow) {
+      event.preventDefault()
+      console.warn('[windows] blocked will-navigate to:', url)
+    }
+  })
+}
+
 function loadRoute(win: BrowserWindow, route: 'main' | 'reminder'): void {
  const devUrl = process.env['ELECTRON_RENDERER_URL']
  if (devUrl) {
@@ -68,10 +110,7 @@ export function createMainWindow(showImmediately = true): BrowserWindow {
    if (showImmediately) win.show()
  })

-  win.webContents.setWindowOpenHandler(({ url }) => {
-    shell.openExternal(url)
-    return { action: 'deny' }
-  })
+  installSafeNavigation(win)

  loadRoute(win, 'main')
  mainWindow = win
@@ -123,6 +162,7 @@ export function createReminderWindow(): BrowserWindow {
  })

  win.setAlwaysOnTop(true, 'screen-saver')
+  installSafeNavigation(win)
  loadRoute(win, 'reminder')

  win.on('closed', () => {
--- a/src/preload/index.ts
+++ b/src/preload/index.ts
@@ -17,7 +17,8 @@ type Unsub = () => void
 type Handler<T> = (payload: T) => void

 function on<T>(channel: string, handler: Handler<T>): Unsub {
-  const listener = (_e: Electron.IpcRendererEvent, payload: T): void => handler(payload)
+  const listener = (_e: Electron.IpcRendererEvent, payload: T): void =>
+    handler(payload)
  ipcRenderer.on(channel, listener)
  return () => ipcRenderer.removeListener(channel, listener)
 }
@@ -44,7 +45,8 @@ const api = {
    ipcRenderer.invoke(IPC.updateSettings, patch),

  getAccentColor: (): Promise<string> => ipcRenderer.invoke(IPC.getAccentColor),
-  getOsTheme: (): Promise<'light' | 'dark'> => ipcRenderer.invoke(IPC.getOsTheme),
+  getOsTheme: (): Promise<'light' | 'dark'> =>
+    ipcRenderer.invoke(IPC.getOsTheme),

  pauseAll: (): Promise<void> => ipcRenderer.invoke(IPC.pauseAll),
  resumeAll: (): Promise<void> => ipcRenderer.invoke(IPC.resumeAll),
@@ -69,17 +71,31 @@ const api = {
  // Challenges
  addChallenge: (input: Omit<Challenge, 'id'>): Promise<Challenge> =>
    ipcRenderer.invoke(IPC.addChallenge, input),
-  updateChallenge: (id: string, patch: Partial<Challenge>): Promise<Challenge> =>
-    ipcRenderer.invoke(IPC.updateChallenge, id, patch),
+  updateChallenge: (
+    id: string,
+    patch: Partial<Challenge>
+  ): Promise<Challenge> => ipcRenderer.invoke(IPC.updateChallenge, id, patch),
  deleteChallenge: (id: string): Promise<boolean> =>
    ipcRenderer.invoke(IPC.deleteChallenge, id),
  toggleChallenge: (id: string, enabled: boolean): Promise<Challenge> =>
    ipcRenderer.invoke(IPC.toggleChallenge, id, enabled),

-  closeMatchSummary: (): Promise<void> => ipcRenderer.invoke(IPC.closeMatchSummary),
+  closeMatchSummary: (): Promise<void> =>
+    ipcRenderer.invoke(IPC.closeMatchSummary),

-  simulateMatchEnd: (id: GameId, stats: Record<string, number>): Promise<void> =>
-    ipcRenderer.invoke('dev:simulateMatchEnd', id, stats),
+  // Dev-only: synthesize a match-end event from the renderer. The channel is
+  // not registered in production builds (see src/main/ipc.ts), so this
+  // function will reject in shipped binaries even though it's exposed.
+  // Gated at the preload level too so the bundler can dead-code-eliminate it.
+  ...(import.meta.env.MODE !== 'production'
+    ? {
+        simulateMatchEnd: (
+          id: GameId,
+          stats: Record<string, number>
+        ): Promise<void> =>
+          ipcRenderer.invoke('dev:simulateMatchEnd', id, stats)
+      }
+    : {}),

  // Auto-updater
  updaterStatus: (): Promise<UpdaterStatus> =>
@@ -99,9 +115,11 @@ const api = {
  onFire: (h: Handler<Exercise>): Unsub => on(IPC.evtFire, h),
  onMatchEnd: (h: Handler<MatchSummary>): Unsub => on(IPC.evtMatchEnd, h),
  onStateChanged: (h: Handler<AppState>): Unsub => on(IPC.evtStateChanged, h),
-  onThemeChanged: (h: Handler<'light' | 'dark'>): Unsub => on(IPC.evtThemeChanged, h),
+  onThemeChanged: (h: Handler<'light' | 'dark'>): Unsub =>
+    on(IPC.evtThemeChanged, h),
  onAccentChanged: (h: Handler<string>): Unsub => on(IPC.evtAccentChanged, h),
-  onGamesChanged: (h: Handler<GameStatus[]>): Unsub => on(IPC.evtGamesChanged, h),
+  onGamesChanged: (h: Handler<GameStatus[]>): Unsub =>
+    on(IPC.evtGamesChanged, h),
  onUpdaterStatus: (h: Handler<UpdaterStatus>): Unsub =>
    on(IPC.evtUpdaterStatus, h)
 }
--- a/src/renderer/src/ReminderApp.tsx
+++ b/src/renderer/src/ReminderApp.tsx
@@ -54,24 +54,16 @@ export default function ReminderApp(): JSX.Element {
    }
  }, [])

+  // ESC closes the match summary view too — keyboard parity with exercise mode.
  useEffect(() => {
-    if (mode.kind !== 'exercise') return
-    const ex = mode.exercise
-    const snoozeMin = settings?.snoozeMinutes ?? 5
+    if (mode.kind !== 'match') return
    function onKey(e: KeyboardEvent): void {
-      if (e.key === 'Enter') {
-        window.api.markDone(ex.id).then(close)
-      } else if (e.key === ' ' || e.code === 'Space') {
-        e.preventDefault()
-        window.api.snooze(ex.id, snoozeMin).then(close)
-      } else if (e.key === 'Escape') {
-        window.api.skip(ex.id).then(close)
-      }
+      if (e.key === 'Escape') close()
    }
    window.addEventListener('keydown', onKey)
    return () => window.removeEventListener('keydown', onKey)
    // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [mode, settings?.snoozeMinutes])
+  }, [mode.kind])

  function close(): void {
    setMode({ kind: 'idle' })
@@ -83,7 +75,10 @@ export default function ReminderApp(): JSX.Element {
  if (mode.kind === 'idle') return <div className="reminder-shell" />
  if (mode.kind === 'exercise') {
    return (
+      // key={exercise.id} forces a fresh component (and fresh stepper state)
+      // when a new reminder arrives while the previous modal is still open.
      <ExerciseReminder
+        key={mode.exercise.id + ':' + mode.exercise.nextFireAt}
        exercise={mode.exercise}
        snoozeMinutes={settings?.snoozeMinutes ?? 5}
        lang={lang}
@@ -97,11 +92,17 @@ export default function ReminderApp(): JSX.Element {
      done={mode.done}
      lang={lang}
      onMarkDone={(id) =>
-        setMode({
+        // Functional update so a second rapid click can't race against a stale
+        // `mode.done` captured in this closure.
+        setMode((m) =>
+          m.kind === 'match'
+            ? {
                kind: 'match',
-          summary: mode.summary,
-          done: new Set([...mode.done, id])
-        })
+                summary: m.summary,
+                done: new Set([...m.done, id])
+              }
+            : m
+        )
      }
      onClose={close}
    />
@@ -124,14 +125,13 @@ function ExerciseReminder({

  const [actualReps, setActualReps] = useState(exercise.reps)
  const adjusted = actualReps !== exercise.reps
+  // Cap the stepper at 5× planned so a stuck "+" button can't log nonsense.
+  const REP_CAP = Math.max(50, exercise.reps * 5)

  async function done(): Promise<void> {
    // Only pass actualReps when user adjusted — otherwise leave undefined
    // so history records the full planned value cleanly.
-    await window.api.markDone(
-      exercise.id,
-      adjusted ? actualReps : undefined
-    )
+    await window.api.markDone(exercise.id, adjusted ? actualReps : undefined)
    onClose()
  }
  async function snooze(): Promise<void> {
@@ -143,7 +143,38 @@ function ExerciseReminder({
    onClose()
  }
  const dec = (): void => setActualReps((n) => Math.max(0, n - 1))
-  const inc = (): void => setActualReps((n) => n + 1)
+  const inc = (): void => setActualReps((n) => Math.min(REP_CAP, n + 1))
+
+  // Keyboard shortcuts live INSIDE the component so they have access to the
+  // current `actualReps` — pressing Enter respects the stepper's adjustment.
+  useEffect(() => {
+    function onKey(e: KeyboardEvent): void {
+      // Don't hijack Space when a button is focused (default activation).
+      const targetTag = (e.target as HTMLElement | null)?.tagName
+      if (e.key === 'Enter') {
+        e.preventDefault()
+        void done()
+      } else if (
+        (e.key === ' ' || e.code === 'Space') &&
+        targetTag !== 'BUTTON'
+      ) {
+        e.preventDefault()
+        void snooze()
+      } else if (e.key === 'Escape') {
+        e.preventDefault()
+        void skip()
+      } else if (e.key === 'ArrowUp' || e.key === '+') {
+        e.preventDefault()
+        inc()
+      } else if (e.key === 'ArrowDown' || e.key === '-') {
+        e.preventDefault()
+        dec()
+      }
+    }
+    window.addEventListener('keydown', onKey)
+    return () => window.removeEventListener('keydown', onKey)
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [actualReps, snoozeMinutes])

  return (
    <div className="reminder-shell flex flex-col h-full">
@@ -181,7 +212,7 @@ function ExerciseReminder({
          <button
            onClick={dec}
            className="w-9 h-9 grid place-items-center rounded-full bg-surface-2 text-text/65 hover:text-text hover:bg-hairline/25 active:scale-90 transition-all"
-            aria-label="−"
+            aria-label={t('reminder.aria.decrement')}
          >
            <Minus size={16} strokeWidth={2.5} />
          </button>
@@ -201,14 +232,17 @@ function ExerciseReminder({
          <button
            onClick={inc}
            className="w-9 h-9 grid place-items-center rounded-full bg-surface-2 text-text/65 hover:text-text hover:bg-hairline/25 active:scale-90 transition-all"
-            aria-label="+"
+            aria-label={t('reminder.aria.increment')}
          >
            <Plus size={16} strokeWidth={2.5} />
          </button>
        </div>
        {adjusted && (
          <div className="text-[12px] text-accent mt-2 font-medium">
-            {t('reminder.partial', { actual: actualReps, planned: exercise.reps })}
+            {t('reminder.partial', {
+              actual: actualReps,
+              planned: exercise.reps
+            })}
          </div>
        )}

@@ -320,7 +354,8 @@ function MatchSummaryView({
        <p className="text-[13px] text-text/65 mt-1.5 font-medium">
          <span className="font-mono-num font-bold text-text">{minutes}</span>{' '}
          {t('fmt.m')} ·{' '}
-          {tn('match.summary.challenges', summary.results.length)}{' · '}
+          {tn('match.summary.challenges', summary.results.length)}
+          {' · '}
          {allDone ? (
            <span className="text-success font-bold">
              {t('match.summary.all_done')}
--- a/src/renderer/src/components/ExerciseCard.tsx
+++ b/src/renderer/src/components/ExerciseCard.tsx
@@ -3,7 +3,7 @@ import { Check, MoreHorizontal } from 'lucide-react'
 import { useState } from 'react'
 import type { Exercise, Tick } from '@shared/types'
 import { Icon } from '../lib/icon'
-import { formatCountdown, formatInterval } from '../lib/format'
+import { formatCountdown } from '../lib/format'
 import { Switch } from './ui/Switch'
 import { useT } from '../i18n'

@@ -78,9 +78,7 @@ export function ExerciseCard({
                strokeLinecap="round"
                strokeDasharray={C}
                strokeDashoffset={dashOffset}
-                className={
-                  isDue ? 'stroke-accent' : 'stroke-accent/85'
-                }
+                className={isDue ? 'stroke-accent' : 'stroke-accent/85'}
                style={{ transition: 'stroke-dashoffset 0.5s linear' }}
              />
            )}
@@ -159,9 +157,7 @@ export function ExerciseCard({
                  isDue ? 'text-accent' : 'text-text'
                ].join(' ')}
              >
-                {exercise.enabled
-                  ? formatCountdown(ms, lang)
-                  : t('fmt.paused')}
+                {exercise.enabled ? formatCountdown(ms, lang) : t('fmt.paused')}
              </div>
            </div>
            <Switch
--- a/src/renderer/src/components/HistoryHeatmap.tsx
+++ b/src/renderer/src/components/HistoryHeatmap.tsx
@@ -83,7 +83,9 @@ export function HistoryHeatmap({
    <div className="bg-surface rounded-2xl p-5 shadow-card dark:ring-0.5 dark:ring-hairline/30">
      <div className="flex items-center gap-2 mb-3">
        <div className="text-[14px] text-text/75 font-semibold">
-          {lang === 'en' ? 'Activity, last 12 weeks' : 'Активность за 12 недель'}
+          {lang === 'en'
+            ? 'Activity, last 12 weeks'
+            : 'Активность за 12 недель'}
        </div>
      </div>

@@ -115,9 +117,7 @@ export function HistoryHeatmap({
              <div key={wi} className="flex flex-col gap-[3px]">
                {w.map((c, di) => {
                  if (!c) {
-                    return (
-                      <div key={di} className="w-[12px] h-[12px]" />
-                    )
+                    return <div key={di} className="w-[12px] h-[12px]" />
                  }
                  const b = bucket(c.reps)
                  const tone =
--- a/src/renderer/src/components/Sidebar.tsx
+++ b/src/renderer/src/components/Sidebar.tsx
@@ -1,13 +1,6 @@
 import { NavLink } from 'react-router-dom'
 import { AnimatePresence, motion } from 'framer-motion'
-import {
-  Sun,
-  Dumbbell,
-  Joystick,
-  Flame,
-  Settings2,
-  X
-} from 'lucide-react'
+import { Sun, Dumbbell, Joystick, Flame, Settings2, X } from 'lucide-react'
 import { useT } from '../i18n'

 type Item = {
--- a/src/renderer/src/components/UpdaterCard.tsx
+++ b/src/renderer/src/components/UpdaterCard.tsx
@@ -94,11 +94,7 @@ function Body({
      <Cell
        tone="info"
        icon={
-          <RefreshCw
-            size={16}
-            strokeWidth={2.4}
-            className="animate-spin"
-          />
+          <RefreshCw size={16} strokeWidth={2.4} className="animate-spin" />
        }
        title={t('updater.checking')}
      />
@@ -145,8 +141,16 @@ function Body({
    )
  }
  if (status.kind === 'downloading') {
-    const pct = Math.max(0, Math.min(100, status.percent || 0))
-    const mb = (n: number): string => (n / 1024 / 1024).toFixed(1)
+    // electron-updater fires early `download-progress` events where some
+    // fields are undefined; guard against NaN/Infinity so we never render
+    // "NaN%" or "NaN MB/s".
+    const rawPct = Number.isFinite(status.percent) ? status.percent : 0
+    const pct = Math.max(0, Math.min(100, rawPct))
+    const mb = (n: number): string =>
+      Number.isFinite(n) ? (n / 1024 / 1024).toFixed(1) : '0.0'
+    const speed = Number.isFinite(status.bytesPerSecond)
+      ? (status.bytesPerSecond / 1024 / 1024).toFixed(2)
+      : '0.00'
    return (
      <div className="px-4 py-4">
        <div className="flex items-center gap-3 mb-3">
@@ -161,7 +165,7 @@ function Body({
              {t('updater.downloading.subtitle', {
                got: mb(status.transferred),
                total: mb(status.total),
-                speed: (status.bytesPerSecond / 1024 / 1024).toFixed(2)
+                speed
              })}
            </div>
          </div>
--- a/src/renderer/src/components/ui/Button.tsx
+++ b/src/renderer/src/components/ui/Button.tsx
@@ -24,15 +24,13 @@ const legacyMap: Record<LegacyVariant, Variant> = {
 }

 const variantClasses: Record<Variant, string> = {
-  filled:
-    'bg-accent text-white hover:brightness-105 active:brightness-95',
+  filled: 'bg-accent text-white hover:brightness-105 active:brightness-95',
  tinted:
    'bg-accent/12 text-accent hover:bg-accent/18 active:bg-accent/22 dark:bg-accent/20 dark:hover:bg-accent/25',
  plain: 'text-accent hover:bg-accent/10 active:bg-accent/15',
  destructive:
    'bg-destructive/12 text-destructive hover:bg-destructive/18 active:bg-destructive/22 dark:bg-destructive/20',
-  success:
-    'bg-success text-white hover:brightness-105 active:brightness-95'
+  success: 'bg-success text-white hover:brightness-105 active:brightness-95'
 }

 const sizeClasses: Record<Size, string> = {
--- a/src/renderer/src/i18n/dict.ts
+++ b/src/renderer/src/i18n/dict.ts
@@ -116,8 +116,7 @@ export const ru: Dict = {
  // Games
  'games.kicker': 'Трекинг матчей',
  'games.title': 'Игры',
-  'games.subtitle':
-    'Подключи игру — челленджи сработают сразу после матча',
+  'games.subtitle': 'Подключи игру — челленджи сработают сразу после матча',
  'games.subtitle.live': '{n} live',
  'games.section.supported': 'Поддерживаемые',
  'games.scanning': 'Сканируем установленные игры…',
@@ -205,6 +204,8 @@ export const ru: Dict = {
  'reminder.reps': 'раз',
  'reminder.next_in': 'Следующее через {interval}',
  'reminder.partial': 'Засчитаем {actual} из {planned}',
+  'reminder.aria.decrement': 'Уменьшить количество повторов',
+  'reminder.aria.increment': 'Увеличить количество повторов',
  'reminder.btn.done': 'Готово',
  'match.title.won': 'Победа',
  'match.title.lost': 'Поражение',
@@ -423,6 +424,8 @@ export const en: Dict = {
  'reminder.reps': 'reps',
  'reminder.next_in': 'Next in {interval}',
  'reminder.partial': "We'll log {actual} of {planned}",
+  'reminder.aria.decrement': 'Decrease rep count',
+  'reminder.aria.increment': 'Increase rep count',
  'reminder.btn.done': 'Done',
  'match.title.won': 'Victory',
  'match.title.lost': 'Defeat',
--- a/src/renderer/src/i18n/index.ts
+++ b/src/renderer/src/i18n/index.ts
@@ -14,17 +14,25 @@ export type TFn = (key: string, vars?: TVars) => string
 /**
 * Look up a key in the dictionary, substitute `{var}` placeholders.
 * Returns the key itself if not found — surfaces missing translations.
+ *
+ * Substitution is done by string split/join rather than a regex so that
+ * variable values containing regex metacharacters (e.g. a user-supplied
+ * exercise name with `$1` or `.*`) are interpolated literally.
 */
-export function translate(
-  lang: Language,
-  key: string,
-  vars?: TVars
-): string {
+export function translate(lang: Language, key: string, vars?: TVars): string {
  const dict = getDict(lang)
-  let s = dict[key] ?? key
+  let s = dict[key]
+  if (s === undefined) {
+    // Surface missing translations in dev; in prod render the key so the user
+    // sees something deterministic instead of a blank.
+    if (import.meta.env.DEV) {
+      console.warn(`[i18n] missing key "${key}" for lang "${lang}"`)
+    }
+    s = key
+  }
  if (vars) {
    for (const k of Object.keys(vars)) {
-      s = s.replace(new RegExp(`\\{${k}\\}`, 'g'), String(vars[k]))
+      s = s.split(`{${k}}`).join(String(vars[k]))
    }
  }
  return s
@@ -37,8 +45,10 @@ export function translate(
 *  many → 0, 5-20, 25-30…
 */
 function pluralRu(n: number): 'one' | 'few' | 'many' {
-  const mod10 = n % 10
-  const mod100 = n % 100
+  // Always pluralize on the absolute value — a "-1" count is the same form as "1".
+  const abs = Math.abs(Math.trunc(n))
+  const mod10 = abs % 10
+  const mod100 = abs % 100
  if (mod10 === 1 && mod100 !== 11) return 'one'
  if (mod10 >= 2 && mod10 <= 4 && (mod100 < 10 || mod100 >= 20)) return 'few'
  return 'many'
@@ -55,12 +65,7 @@ export function translateN(
  n: number,
  vars?: TVars
 ): string {
-  const form =
-    lang === 'ru'
-      ? pluralRu(n)
-      : n === 1
-        ? 'one'
-        : 'many'
+  const form = lang === 'ru' ? pluralRu(n) : n === 1 ? 'one' : 'many'
  return translate(lang, `${keyBase}_${form}`, { n, ...vars })
 }

--- a/src/renderer/src/lib/format.ts
+++ b/src/renderer/src/lib/format.ts
@@ -7,7 +7,7 @@ const SUFFIX = {

 export function formatCountdown(ms: number, lang: Language = 'ru'): string {
  const s = SUFFIX[lang] ?? SUFFIX.ru
-  if (ms <= 0) return s.now
+  if (!Number.isFinite(ms) || ms <= 0) return s.now
  const totalSec = Math.floor(ms / 1000)
  const h = Math.floor(totalSec / 3600)
  const m = Math.floor((totalSec % 3600) / 60)
@@ -17,10 +17,7 @@ export function formatCountdown(ms: number, lang: Language = 'ru'): string {
  return `${sec}${s.s}`
 }

-export function formatInterval(
-  minutes: number,
-  lang: Language = 'ru'
-): string {
+export function formatInterval(minutes: number, lang: Language = 'ru'): string {
  const s = SUFFIX[lang] ?? SUFFIX.ru
  if (minutes < 60) return `${minutes} ${s.minLong}`
  const h = Math.floor(minutes / 60)
--- a/src/renderer/src/lib/history.test.ts
+++ b/src/renderer/src/lib/history.test.ts
@@ -94,19 +94,12 @@ describe('currentStreak', () => {
  })

  it('ignores skip and snooze', () => {
-    const hist = [
-      entry('a', day(0), 'skip'),
-      entry('a', day(1), 'snooze')
-    ]
+    const hist = [entry('a', day(0), 'skip'), entry('a', day(1), 'snooze')]
    expect(currentStreak(hist)).toBe(0)
  })

  it('multiple entries same day count once', () => {
-    const hist = [
-      entry('a', day(0)),
-      entry('b', day(0)),
-      entry('a', day(1))
-    ]
+    const hist = [entry('a', day(0)), entry('b', day(0)), entry('a', day(1))]
    expect(currentStreak(hist)).toBe(2)
  })
 })
--- a/src/renderer/src/lib/history.ts
+++ b/src/renderer/src/lib/history.ts
@@ -1,7 +1,5 @@
 import type { Exercise, HistoryEntry } from '@shared/types'

-const MS_DAY = 24 * 60 * 60 * 1000
-
 /** YYYY-MM-DD in local time. */
 export function dayKey(ts: number): string {
  const d = new Date(ts)
@@ -16,6 +14,18 @@ export function todayKey(): string {
  return dayKey(Date.now())
 }

+/**
+ * Return a new Date offset by `dayDelta` calendar days from `base`, with the
+ * time-of-day preserved. Uses `setDate` (calendar arithmetic) rather than
+ * subtracting `n * 24h` of milliseconds — across DST transitions ms arithmetic
+ * drifts by ±1h and `dayKey` can emit the wrong day.
+ */
+function shiftDays(base: Date, dayDelta: number): Date {
+  const d = new Date(base.getTime())
+  d.setDate(d.getDate() + dayDelta)
+  return d
+}
+
 /**
 * Reps logged on a given local day. Uses `actualReps` if present, otherwise
 * looks up exercise's planned `reps`.
@@ -46,28 +56,27 @@ export function dailyRepsRange(
 ): { key: string; date: Date; reps: number }[] {
  const today = new Date()
  today.setHours(0, 0, 0, 0)
-  const buckets = new Map<string, number>()
+  const buckets = new Map<string, { date: Date; reps: number }>()
  const byId = new Map(exercises.map((e) => [e.id, e]))

-  // Seed all days with 0 so heatmap renders contiguous.
+  // Seed all days with 0 so heatmap renders contiguous. Use calendar arithmetic
+  // (setDate) — DST transitions would shift epoch-based math by ±1h, causing
+  // dayKey() to emit duplicate or missing days at the boundary.
  for (let i = days - 1; i >= 0; i--) {
-    const d = new Date(today.getTime() - i * MS_DAY)
-    buckets.set(dayKey(d.getTime()), 0)
+    const d = shiftDays(today, -i)
+    buckets.set(dayKey(d.getTime()), { date: d, reps: 0 })
  }

  for (const e of entries) {
    if (e.action !== 'done') continue
    const k = dayKey(e.ts)
-    if (!buckets.has(k)) continue
+    const bucket = buckets.get(k)
+    if (!bucket) continue
    const reps = e.actualReps ?? byId.get(e.exerciseId)?.reps ?? 0
-    buckets.set(k, (buckets.get(k) ?? 0) + reps)
+    bucket.reps += reps
  }

-  return Array.from(buckets, ([key, reps]) => ({
-    key,
-    date: new Date(`${key}T00:00:00`),
-    reps
-  }))
+  return Array.from(buckets, ([key, { date, reps }]) => ({ key, date, reps }))
 }

 /**
@@ -84,21 +93,22 @@ export function currentStreak(entries: HistoryEntry[]): number {

  const today = new Date()
  today.setHours(0, 0, 0, 0)
+  const yesterday = shiftDays(today, -1)
  const todayK = dayKey(today.getTime())
-  const yesterdayK = dayKey(today.getTime() - MS_DAY)
+  const yesterdayK = dayKey(yesterday.getTime())

  // Start from today if active today, else yesterday (grace), else 0.
-  let cursor = doneDays.has(todayK)
+  let cursor: Date | null = doneDays.has(todayK)
    ? today
    : doneDays.has(yesterdayK)
-      ? new Date(today.getTime() - MS_DAY)
+      ? yesterday
      : null
  if (!cursor) return 0

  let streak = 0
  while (doneDays.has(dayKey(cursor.getTime()))) {
    streak++
-    cursor = new Date(cursor.getTime() - MS_DAY)
+    cursor = shiftDays(cursor, -1)
  }
  return streak
 }
--- a/src/renderer/src/lib/icon.tsx
+++ b/src/renderer/src/lib/icon.tsx
@@ -24,13 +24,27 @@ export const ICON_CHOICES = [

 export type IconName = (typeof ICON_CHOICES)[number]

+const ICON_SET = new Set<string>(ICON_CHOICES)
+
+/**
+ * Render a Lucide icon by name. Restricted to the curated ICON_CHOICES set —
+ * an arbitrary string from a corrupted state file could otherwise resolve to
+ * unrelated Lucide exports (`default`, `createLucideIcon`, etc.) and crash
+ * the renderer.
+ */
 export function Icon({
  name,
  ...props
 }: { name: string } & LucideProps): JSX.Element {
-  const Cmp = (Lucide as unknown as Record<string, React.ComponentType<LucideProps>>)[
-    name
-  ]
+  if (!ICON_SET.has(name)) {
+    if (import.meta.env.DEV) {
+      console.warn(`[Icon] unknown icon name "${name}" — falling back`)
+    }
+    return <Lucide.Activity {...props} />
+  }
+  const Cmp = (
+    Lucide as unknown as Record<string, React.ComponentType<LucideProps>>
+  )[name]
  if (!Cmp) return <Lucide.Activity {...props} />
  return <Cmp {...props} />
 }
--- a/src/renderer/src/main.tsx
+++ b/src/renderer/src/main.tsx
@@ -10,6 +10,8 @@ const which = params.get('window') ?? 'main'

 ReactDOM.createRoot(document.getElementById('root')!).render(
  <React.StrictMode>
-    <ThemeProvider>{which === 'reminder' ? <ReminderApp /> : <App />}</ThemeProvider>
+    <ThemeProvider>
+      {which === 'reminder' ? <ReminderApp /> : <App />}
+    </ThemeProvider>
  </React.StrictMode>
 )
--- a/src/renderer/src/pages/Exercises.tsx
+++ b/src/renderer/src/pages/Exercises.tsx
@@ -130,9 +130,7 @@ function ExerciseRow({
      <div
        className={[
          'w-9 h-9 rounded-lg grid place-items-center shrink-0',
-          exercise.enabled
-            ? 'bg-accent text-white'
-            : 'bg-text/15 text-text/45'
+          exercise.enabled ? 'bg-accent text-white' : 'bg-text/15 text-text/45'
        ].join(' ')}
      >
        <Icon name={exercise.icon} size={18} strokeWidth={2.2} />
--- a/src/renderer/src/pages/Games.tsx
+++ b/src/renderer/src/pages/Games.tsx
@@ -54,9 +54,7 @@ export default function GamesPage(): JSX.Element {
    }
  }

-  const liveCount = games.filter(
-    (g) => g.enabled && g.integrationActive
-  ).length
+  const liveCount = games.filter((g) => g.enabled && g.integrationActive).length

  return (
    <div className="h-full overflow-y-auto">
@@ -170,11 +168,7 @@ function GameCard({
          </div>
        </div>
        {game.installed && game.integrationActive && (
-          <Switch
-            checked={game.enabled}
-            onChange={onToggle}
-            disabled={busy}
-          />
+          <Switch checked={game.enabled} onChange={onToggle} disabled={busy} />
        )}
      </div>

@@ -280,8 +274,16 @@ function StatusBadge({
 function DevPanel({ games }: { games: GameStatus[] }): JSX.Element | null {
  const [open, setOpen] = useState(false)
  const { t } = useT()
+  // Never render in packaged builds — the matching IPC handler is also
+  // unregistered there, so the buttons would do nothing anyway.
+  if (!import.meta.env.DEV) return null
  const dota = games.find((g) => g.id === 'dota2')
  if (!dota?.enabled) return null
+  // In dev the preload exposes window.api.simulateMatchEnd; the conditional
+  // type still hides it, so we narrow here.
+  const api = window.api as typeof window.api & {
+    simulateMatchEnd?: (id: 'dota2', stats: Record<string, number>) => void
+  }
  return (
    <div className="mt-10">
      <button
@@ -305,7 +307,7 @@ function DevPanel({ games }: { games: GameStatus[] }): JSX.Element | null {
          ).map((p) => (
            <button
              key={p.label}
-              onClick={() => window.api.simulateMatchEnd('dota2', p.stats)}
+              onClick={() => api.simulateMatchEnd?.('dota2', p.stats)}
              className="text-[12px] px-3 py-1.5 rounded-full bg-surface-2 hover:bg-accent/15 hover:text-accent text-text/70 font-medium transition-colors active:scale-95"
            >
              {p.label}
--- a/src/renderer/src/providers/ThemeProvider.tsx
+++ b/src/renderer/src/providers/ThemeProvider.tsx
@@ -1,7 +1,11 @@
 import { ReactNode, useEffect, useState } from 'react'
 import { useAppStore } from '../store/appStore'

-export function ThemeProvider({ children }: { children: ReactNode }): JSX.Element {
+export function ThemeProvider({
+  children
+}: {
+  children: ReactNode
+}): JSX.Element {
  const settings = useAppStore((s) => s.state?.settings)
  const [osTheme, setOsTheme] = useState<'light' | 'dark'>('dark')

--- a/src/renderer/src/store/appStore.ts
+++ b/src/renderer/src/store/appStore.ts
@@ -31,7 +31,9 @@ export const useAppStore = create<Store>((set) => ({
 export function subscribeToBackend(): () => void {
  const store = useAppStore.getState()
  store.hydrate()
-  const u1 = window.api.onStateChanged((s) => useAppStore.getState().setState(s))
+  const u1 = window.api.onStateChanged((s) =>
+    useAppStore.getState().setState(s)
+  )
  const u2 = window.api.onTick((t) => useAppStore.getState().setTicks(t))
  return () => {
    u1()
--- a/src/renderer/src/styles/globals.css
+++ b/src/renderer/src/styles/globals.css
@@ -114,8 +114,8 @@ body {
 }

 .font-mono-num {
-  font-family: 'JetBrains Mono', ui-monospace, 'SF Mono', 'Cascadia Code',
-    Menlo, monospace;
+  font-family:
+    'JetBrains Mono', ui-monospace, 'SF Mono', 'Cascadia Code', Menlo, monospace;
  font-variant-numeric: tabular-nums;
  font-feature-settings: 'ss02', 'ss19', 'zero';
  letter-spacing: -0.01em;
--- a/src/shared/quiet-hours.test.ts
+++ b/src/shared/quiet-hours.test.ts
@@ -58,6 +58,38 @@ describe('isQuietAt', () => {
    expect(isQuietAt(qh, at('2026-05-18T13:30:00'))).toBe(true)
  })

+  it('wrap-around + day filter: window day matters, not current day', () => {
+    // from=22:00, to=07:00, days=[Mon..Fri].
+    const qh: QuietHours = {
+      enabled: true,
+      from: '22:00',
+      to: '07:00',
+      days: [1, 2, 3, 4, 5]
+    }
+    // Friday 23:00 -> window starts today, Friday in filter -> quiet
+    expect(isQuietAt(qh, at('2026-05-15T23:00:00'))).toBe(true)
+    // Saturday 02:00 -> window started Friday 22:00, Friday in filter -> quiet
+    expect(isQuietAt(qh, at('2026-05-16T02:00:00'))).toBe(true)
+    // Saturday 23:00 -> would start today, Saturday not in filter -> noisy
+    expect(isQuietAt(qh, at('2026-05-16T23:00:00'))).toBe(false)
+    // Sunday 02:00 -> started Saturday, Saturday not in filter -> noisy
+    expect(isQuietAt(qh, at('2026-05-17T02:00:00'))).toBe(false)
+    // Monday 01:00 -> would have started Sunday, Sunday not in filter -> noisy
+    expect(isQuietAt(qh, at('2026-05-18T01:00:00'))).toBe(false)
+    // Monday 23:00 -> starts today, Monday in filter -> quiet
+    expect(isQuietAt(qh, at('2026-05-18T23:00:00'))).toBe(true)
+  })
+
+  it('malformed from/to falls back to non-quiet', () => {
+    const qh: QuietHours = {
+      enabled: true,
+      from: 'bogus',
+      to: '08:00',
+      days: ALL_DAYS
+    }
+    expect(isQuietAt(qh, at('2026-05-17T05:00:00'))).toBe(false)
+  })
+
  it('zero-length window (from === to) is never quiet', () => {
    const qh: QuietHours = {
      enabled: true,
--- a/src/shared/types.ts
+++ b/src/shared/types.ts
@@ -176,33 +176,81 @@ export const DEFAULT_SETTINGS: Settings = {
  }
 }

+const HHMM_RE = /^(\d{1,2}):(\d{2})$/
+
+/** Parse `HH:MM` into minutes-since-midnight, or `null` if malformed. */
+function parseHHMM(s: string): number | null {
+  const m = HHMM_RE.exec(s)
+  if (!m) return null
+  const h = Number(m[1])
+  const min = Number(m[2])
+  if (!Number.isFinite(h) || !Number.isFinite(min)) return null
+  if (h < 0 || h > 23 || min < 0 || min > 59) return null
+  return h * 60 + min
+}
+
 /**
 * Returns true if `now` falls inside the quiet window. Handles wrap-around
- * windows (e.g. 22:00 → 08:00). Exposed from shared so both main scheduler
- * and renderer settings UI can use the same logic.
+ * windows (e.g. 22:00 → 08:00) AND day-of-week filtering correctly: when the
+ * window started the previous day (we're in the AM half of a wrap-around),
+ * the day filter is evaluated against the START day, not the current day.
+ *
+ * Example: from=22:00, to=07:00, days=[Mon..Fri]. At Sat 02:00 the window
+ * is active (started Fri 22:00 — Friday is in the filter). At Mon 01:00 the
+ * window is NOT active (would have started Sun 22:00 — Sunday is excluded).
+ *
+ * Malformed `from`/`to` strings (after a corrupt state file) return false.
 */
 export function isQuietAt(qh: QuietHours, now: Date): boolean {
  if (!qh.enabled) return false
-  const dow = now.getDay() // 0..6
-  if (qh.days.length > 0 && !qh.days.includes(dow)) return false
-  const [fh, fm] = qh.from.split(':').map(Number)
-  const [th, tm] = qh.to.split(':').map(Number)
-  const cur = now.getHours() * 60 + now.getMinutes()
-  const fromMin = fh * 60 + fm
-  const toMin = th * 60 + tm
+  const fromMin = parseHHMM(qh.from)
+  const toMin = parseHHMM(qh.to)
+  if (fromMin === null || toMin === null) return false
  if (fromMin === toMin) return false
+
+  const cur = now.getHours() * 60 + now.getMinutes()
+  const todayDow = now.getDay() // 0..6, 0=Sunday
+  const yesterdayDow = (todayDow + 6) % 7
+
+  // Helper: is this day included by the filter?
+  const dayActive = (dow: number): boolean =>
+    qh.days.length === 0 || qh.days.includes(dow)
+
  if (fromMin < toMin) {
-    // Same-day window.
+    // Same-day window — start day is `todayDow`.
+    if (!dayActive(todayDow)) return false
    return cur >= fromMin && cur < toMin
  }
-  // Wraps midnight: active if after `from` today OR before `to` today.
-  return cur >= fromMin || cur < toMin
+  // Wrap-around window. Either:
+  //   - cur >= fromMin: window started TODAY at fromMin → check todayDow
+  //   - cur < toMin: window started YESTERDAY at fromMin → check yesterdayDow
+  if (cur >= fromMin) return dayActive(todayDow)
+  if (cur < toMin) return dayActive(yesterdayDow)
+  return false
 }

 export const SAMPLE_EXERCISES: Omit<Exercise, 'id' | 'nextFireAt'>[] = [
-  { name: 'Приседания', reps: 10, icon: 'Activity', intervalMinutes: 30, enabled: true },
-  { name: 'Отжимания', reps: 10, icon: 'Dumbbell', intervalMinutes: 45, enabled: true },
-  { name: 'Растяжка спины', reps: 1, icon: 'StretchHorizontal', intervalMinutes: 60, enabled: false }
+  {
+    name: 'Приседания',
+    reps: 10,
+    icon: 'Activity',
+    intervalMinutes: 30,
+    enabled: true
+  },
+  {
+    name: 'Отжимания',
+    reps: 10,
+    icon: 'Dumbbell',
+    intervalMinutes: 45,
+    enabled: true
+  },
+  {
+    name: 'Растяжка спины',
+    reps: 1,
+    icon: 'StretchHorizontal',
+    intervalMinutes: 60,
+    enabled: false
+  }
 ]

 export type UpdaterStatus =
@@ -220,4 +268,3 @@ export type UpdaterStatus =
    }
  | { kind: 'downloaded'; version: string }
  | { kind: 'error'; message: string }
-
--- a/tsconfig.node.json
+++ b/tsconfig.node.json
@@ -11,7 +11,7 @@
    "skipLibCheck": true,
    "resolveJsonModule": true,
    "isolatedModules": true,
-    "types": ["electron-vite/node"],
+    "types": ["electron-vite/node", "vite/client"],
    "baseUrl": ".",
    "paths": {
      "@shared/*": ["src/shared/*"]
--- a/tsconfig.web.json
+++ b/tsconfig.web.json
@@ -14,6 +14,7 @@
    "isolatedModules": true,
    "noEmit": true,
    "useDefineForClassFields": true,
+    "types": ["vite/client"],
    "baseUrl": ".",
    "paths": {
      "@renderer/*": ["src/renderer/src/*"],